As a special kind of computer peripheral equipment, touch screens are the simplest and most convenient human-computer interaction means until now, and extensively used in the portable electronic devices. At present, the major manufacturers adopt a process of depositing a whole layer of silicon oxide or silicon oxynitride layer on an ITO (Tin Oxide Indium) layer in the production of a touch screen, so as to realize the effect of shadow elimination, insulation, and protection. Before bonding a flexible printed circuit (FPC) to the touch screen, the silicon oxynitride layer for example corresponding to the bonding region, in which the FPC is bonded (i.e. bonding region), should be removed first. However, the major manufacturers currently adopt the following insulation layer remove method: after evenly stirring an etching paste, coating the etching paste to the region of interest on the touch screen through a screen printing method, then after a predetermined time period, spraying water to the region to clean the touch screen, whereby the silicon oxynitride layer in the region can be removed along with the water cleaning. However, this method wastes a lot of etching paste in the process, and needs consumptive materials such as screen printing plate, and therefore, the production cost is increased and the operation ratio of the production line is decreased.